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Soil Drainage and Productivity Indexes


Photograph of a well-drained Mollisol (a Lithic Hapludoll), with a Drainage Index of 33. The shallowness of the bedrock lowers the water-holding capacity of the soil, hence the low DI value. Photo by Randall Schaetzl, Department of Geography, Michigan State University.
Photograph of a well-drained Mollisol (a Lithic Hapludoll), with a Drainage Index of 33. The shallowness of the bedrock lowers the water-holding capacity of the soil, hence the low DI value. (Photo courtesy of Randall Schaetzl, Department of Geography, Environment, and Spatial Sciences of Michigan State University)

This webpage provides information on the Drainage Index (DI) and Productivity Index (PI) of all soils that are classified within the US system of Soil Taxonomy. These data aid in the identification of areas at risk to various forest insects and diseases because of their ability to identify regions of potential tree stress (see the 2013-2027 National Insect and Disease Forest Risk Assessment).

For help with soil taxonomy terminology, please visit NRCS Soil Taxonomy. This work was performed under the supervision of Dr. Randall Schaetzl, Department of Geography, Environment, and Spatial Sciences of Michigan State University, under contract with (and supported by) the US Forest Service.

Please note that the tabular and GIS data downloads from this site have been updated using the 2023 gNATSGO database.

Soil Drainage Index

The Drainage Index (DI), originally named the "natural soil wetness index" (Hole and Campbell 1986, Schaetzl 1986), is a measure of long-term soil wetness. It is designed to represent, as an ordinal number, the amount of water that a soil contains and makes available to plants under normal climatic conditions. It is not meant to mimic the concept of "plant available water", which is mostly dependent upon soil texture. The DI only loosely/secondarily takes soil texture into consideration. The main factor affecting the DI is the depth to the water table and the soil volume available for plants to root and grow in. The DI concept was first initiated by Hole (1978) and Hole and Campbell (1985), and expanded upon by Schaetzl (1986).

Photograph of a somewhat excessively-drained Spodosol (a Typic Haplorthod), with a Drainage Index of 40. Note the prominent
Photograph of a somewhat excessively-drained Spodosol (a Typic Haplorthod), with a Drainage Index of 40. Note the prominent "tongues" in this soil - typical of many Spodosols. (Photo courtesy of Randall Schaetzl, Department of Geography, Environment, and Spatial Sciences of Michigan State University)

The DI ranges from 0 to 99. The higher the DI, the more water the soil can and does, theoretically, supply to plants. Sites with DI values of 99 are essentially open water. A DI of zero indicates impermeable surfaces like bare bedrock or urban areas dominated by pavement and buildings.  The DI is derived from the soil's taxonomic subgroup classification in the US system of Soil Taxonomy, and (optionally) its soil map slope class.

Because a soil's taxonomic classification is not (initially) affected by such factors as irrigation or artificial drainage, the DI does not change as soils become irrigated or drained (unless the long-term effects of this involve a change in the soil's taxonomic classification). Instead, the DI reflects the soil's NATURAL wetness condition. Each soil SERIES has, in theory, its own unique DI. Some soil series span two or more drainage classes; in this case the DI that is used is the one that would normally be used for a soil with that subgroup classification.

Schaetzl, R.J., Krist, F.J. Jr., Stanley, K.E., and C.M. Hupy. 2009. The Natural Soil Drainage Index: An Ordinal Estimate of Long-Term, Soil Wetness. Physical Geography 30:383-409. (3.5 MB PDF)

Soil Productivity Index

Photograph of a poorly-drained Inceptisol (a Typic Endoaquept), with a Drainage Index of 80. Photo by Randall Schaetzl, Department of Geography, Michigan State University.
Photograph of a poorly-drained Inceptisol (a Typic Endoaquept), with a Drainage Index of 80. (Photo courtesy of Randall Schaetzl, Department of Geography, Environment, and Spatial Sciences of Michigan State University)

Like the DI, the Productivity Index (PI) is an ordinal measure, but of the productivity of a soil. The PI uses family-level Soil Taxonomy information, i.e., interpretations of taxonomic features or properties that tend to be associated with low or high soil productivity, to rank soils from 1 (least productive) to 19 (most productive) a PI of 0 are non-soil locations (water, impermeable surfaces.

The index has wide application, because, unlike competing indexes, it does not require copious amounts of soil data, e.g., pH, organic matter, or CEC, in its derivation. GIS applications of the PI, in particular, have great potential. For regionally extensive applications, the PI may be as useful and robust as other productivity indexes that have much more exacting data requirements.

Schaetzl, R.J. Krist, F.J. Jr., and B.A. Miller. 2012. A Taxonomically Based, Ordinal Estimate of Soil Productivity for Landscape-Scale Analyses. Soil Science 177:288-299. (PDF, 7.1 MB)

References

Hole, F.D. 1978. An approach to landscape analysis with emphasis on soils. Geoderma 21:1-13.
Hole, F.D. and J.B. Campbell. 1985. Soil Landscape Analysis. Rowman and Allanheld, Totowa, NJ 196 pp.
Schaetzl, R.J. 1986. A soilscape analysis of contrasting glacial terrains in Wisconsin. Annals Assoc. Am. Geogs. 76:414-425.

Contacts

For more details about the DI and/or PI workings and theory, to request more detailed copies of posters or have questions answered, contact Dr. Randall Schaetzl at the Department of Geography, Environment, and Spatial Sciences of Michigan State University.


Data Downloads

Soil Drainage Index (DI) and Productivity Index (PI) Map Unit and Component lookup tables were updated in August of 2024 using a 2023 gNATSGO database download from the USDA NRCS Soils download site (https://nrcs.app.box.com/v/soils/). The updated Map Unit DI and PI lookup table were then joined to the 30-meter MURASTER raster file included in the 2023 CONUS gNATSGO file geodatabase. 
The DI and PI rasters for the lower 48 states and Washington DC (CONUS) are available for download as zipped geotiffs. If users experience difficulties downloading these large, CONUS-wide, files we also provide the DI and PI 30-meter rasters in smaller, multi-state partitions.  
Users can obtain Map Unit polygon vectors for individual states from the USDA NRCS soils download site. The state-level MUPOLYGON map unit polygon layers can be joined and related to the Map Unit and Component DI_PI tables in the ‘L48_MapUnits_Components_w_DI_PI_2023.gdb’ file geodatabase based on the MUKEY join field.

  • NOTE: The vast majority of these circa 2023 DI and PI lookups will properly join to more current versions of USDA soil MURASTER and MUPOLY layers. However newly soil surveyed areas will receive new MUKEYs that will have no join to these 2023 tables. And in some cases, soil properties of existing MUKEYs will get updates that could cause 2023 DI and PI values for those MUKEY joins to be outdated.

In addition to the zipped file geodatabase download, DI and PI Map Unit and Component lookup tables are also available in an Excel format. Also downloadable, is an Excel Soil Series table with fields added for series DI and PI values. Based on matches of soil taxonomy the 2023 Soil Series and Map Unit/Component DI and PI Excel workbooks could be used to determine DI and PI values for new (post 2023) soil survey Map Units.

Downloadable Documentation and Tables
DESCRIPTIONFILE TYPE/SIZE
DI and PI 30-meter raster READMEDOCX, 20 KB
DI-PI Map Unit & Component join tables (GDB file)ZIP, 21 MB
DI-PI Map Unit & Component join tables (Excel file)XLSX, 72 MB
DI modifiers tablePDF, 87 KB
PI modifiers tablePDF, 122 KB
DI and PI by Soil SeriesXLSX, 4 MB
Drainage Index (DI) and Productivity (PI) 30-meter raster downloads (zipped geoTiffs)
REGIONSTATESDI ZIP FILE/SIZEPI ZIP FILE/SIZE
CONUSAll states and Washington DC in Continental USDI, 1.5 GBPI, 1.4 GB
NorthcentralIllinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Ohio, WisconsinDI, 383 MBPI, 334 MB
Northcentral WestMontana, Nebraska, North Dakota, South Dakota, WyomingDI, 251 MBPI, 236 MB
NortheastConnecticut, Delaware, District of Columbia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West VirginiaDI, 171 MBPI, 147 MB
NorthwestIdaho, Oregon, WashingtonDI, 83 MBPI, 79 MB
Southcentral WestColorado, Kansas, New Mexico, Oklahoma, TexasDI, 278 MBPI, 267 MB
SoutheastAlabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, TennesseeDI, 245 MBPI, 223 MB
SouthwestArizona, California, Nevada, UtahDI, 126 MBPI, 122 MB

Research Links

Combining National Forest Inventory Data with Soil Drainage Index to Assess Forest Health Vulnerability Poster
Combining National Forest Inventory Data with Soil Drainage Index to Assess Forest Health Vulnerability Poster.
Downloadable Research Files
DESCRIPTIONFILE TYPE/SIZE
2019 Poster: "Combining National Forest Inventory Data with Soil Drainage Index to Assess Forest Health Vulnerability"PDF, 2 MB
PI manuscript (2012): "A Taxonomically Based Ordinal Estimate of Soil Productivity for Landscape-Scale Analyses"PDF, 7 MB
DI manuscript (2009): "The Natural Soil Drainage Index: An Ordinal Estimate of Long-Term Soil Wetness"PDF, 3.5 MB
2012 Poster: "The Soil Productivity Index: Taxonomically Based, Ordinal Estimates of Soil Productivity"PDF, 3.5 MB
2011 Poster: "Landscape (Soil) Wetness Map of the Conterminous United States" Presented at the 2011 Esri International Users Conference, San Diego, CA, in 2012PDF, 4 MB
ESRI's Interactive Flash Player Map Book Volume 27: Landscape (Soil) Wetness Map of the Conterminous United States (see pages 70-71)Web link
2011 Poster: "The Soil Fertility and Drainage Indexes: Taxonomically Based, Ordinal Estimates of Relative Soil Properties"PDF, 3.5 MB
2008 Poster: "Introducing and Applying a Soil Wetness Index Designed for Modeling, GIS and Mapping Applications"  Presented at the 11th North American Forest Soils Conference, Blacksburg, VA, in 2008PDF, 1.6 MB
2007 Poster: "Using the New Natural Soil Drainage Index to Highlight and Explain Soil Wetness Patterns in Michigan"  Presented at the annual meeting of the Michigan Academy of Science, Arts and Letters, Big Rapids, MI, in 2007PDF, 1.4 MB
2007 Poster: "Introducing a New Index of Soil Wetness, and its Potential as a Landscape/Landform Visualization Tool" Presented at the north-central regional meeting of the Geological Society of America, in Lawrence, KS, in 2007PDF, 1.3 MB
2006 Poster: "The National Soil Drainage Index Map, a Factor in Forest Health Risk Assessment"PDF, 14 MB

Pi-Di Citations

A selection of papers and theses that have cited/used the Productivity and Drainage indices.

Soil Productivity Index and Soil Drainage Index

 

Soil Productivity Index

 

Soil Drainage Index